Uninterrupted Power Supply System can be directly started by the battery pack through unique DC-start-up function in absence of utility power, which exerts the urgent back-up function of UPS. The Uninterrupted Power Supply System is designed to provide up to 4 hour backup. The Uninterrupted Power Supply System is fitted with RS 232 communication port which ensures that the status of the power supply and the UPS system can be directly monitored on the computer screen. Uninterrupted Power Supply System adopts PFC technology at power input terminal and the input power factor is more than 0.95. The Uninterrupted Power Supply System has automatic self diagnosis facility and when the UPS is powered on, it immediately performs an inspection of the components such as inverter, battery and load, to detect any problem in time to avoid causing any negligence or loss. Uninterrupted Power Supply System performs real time alarm silence function which eliminates the unnecessary annoying noise.